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<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        //全局的变量
        let a = 10 ;
        //console.log(window.a);
       //let a  =10 ;
       {
            let c =20 ; 
       }

       //console.log(c);


       function func(){
            //局部变量
            let d = 30 ; 
       }
       func();
       console.log(d)
    </script>
</body>
</html>